Page 15 - Computer Science V2.0 Class 11

Unit I: Computer Systems and Organisation

1 COMPUTER FUNDAMENTALS

Chapter Outline

1.1 CPU 1.2 Input Devices
1.3 Output Devices 1.4 Memory Unit
1.5 Software

Introduction

Computing technology has impacted almost every facet of our life. Examples of computing technology include creating
a document, making a presentation on a project that you have developed for a course, shopping on an e-commerce
site, managing inventory in a store, e-learning, watching a video on YouTube, booking a ticket for a train or a flight,
medical diagnosis and treatment, maintenance of medical records, and means of entertainment like making of films,
video games, and puzzles, making a hotel reservation, a phone call on your mobile, or online payment of bills. Thus,
the computer has become an integral part of our lives.
Now, being aware of so many applications of computers, can you find a generic answer to the following question,
which applies to all the applications mentioned above: What does a computer do? Well, the answer is simple: It
produces some information which is required by the user depending on the need. For example, you may be interested
to see on a computer the average marks of students in a class, or you may like to design a painting and print it on paper
using a colour printer, or you may want to listen to the music of your preferred type on a mobile, or you may like the
broom of a robot to clean the floor. So, to produce a useful output for us, a computer must have an output unit that
can deliver the desired output on a suitable device, called an output device. Thus, a monitor that displays the average
marks of students in a class, a printer that prints a painting on paper, or the speaker of a mobile phone that plays our
favourite music, are examples of output devices. To produce something useful, we must be able to give instructions to
the computer. To take these instructions from us, it must have an input unit. A keyboard is the most common example
of an input device. Further, a computer must be able to process our instructions. Hence, it must have a processing unit,
say, Central Processing Unit (CPU). While processing, the data and (such as marks of students in a class) instructions
must be stored somewhere. So, a computer must have a memory unit.
To summarise, a computer is an electronic device that accepts input data from the user, processes it, and produces
results. It comprises of the following components (see Fig 1.1):
Input Unit
Central Processing Unit (CPU)
Memory Unit
Output Unit

Computer Fundamentals 1